Switching device



Nov, 18, 1924.

O. F. FORSBERG SWITCHING DEVICE Filed Nov. l5 1921 waag ,En

Hung@ s Emi i /m/e/i/b/' Oscar/ @Amay y MLZL/Wg sha mhlw M www www Patented Nov. 18, 1924.

UNITED STATES PATENT OFFICE.

OSCAR F. FORSBERG, OFv YONKERS, NEW YORK, ASSIGNOR TO WESTERN ELECTRIC COMPANY, INCORPORATED, 0F NEW YORK, N. Y., A CORPORATION OF NEW YORK.

SWITCHING DEVICE.

Application led November 15, 1921. Serial `No. 515,358.

To all fwlwmy v'zf may concern:

Be it known that I, OSCAR F. Fonsnno, a citizen of the United States, residing at Yonkers, in the county of Westchester, State of New York, have invented certain new and useful Improvements in Switching Devices, of which the following is a full, clear, conoise, and exact description.

This invention relates to switching apparatus and more particularly concerns switching structures in which a multiplicity of electrical circuit connections are established by the cooperation of contact elements. K

The object of this invention is to provide for securing a relative movement between thc cooperating circuit making contact elements of switching devices of this character during the time said contact elements are in physical engagement with each other.

A feature of the invention relates to a switching mechanism, comprising cooperating passive contact elements and active con tact elements, in which an active element is arranged to be displaced longitudinally while in engagement with one of the passive elements to effect a change in the point of engagement.

Another feature of the invention relates to a switching mechanism comprising a plurality of passive contact elements and an active contact element having a different point of cooperation with each passive element in which the active element is adapted to be bodily displaced longitudinally while in cngagement with any one of the passive elements to effect a change in the point of en gagement.

A still further feature is the provision of means, in a switch consisting of a plurality of passive contacts and a movable bare wire conductor serving as a coacting contact for said passive contacts, for displacing,r said movable wire in the direction of its length to cause `it to rub over the passive contacts.

These and such other features of invention as are contemplated in the present application will become more apparent 'from the following detailed description and from the appended claims.

Referring to the drawing forming a part of the application, Fig. 1 shows a side view of a switching device to which the features of the invention are applicable, and Fig. 2 is a fragmentary view of the switching mech- `anism, taken in perspective, and illustrating the manner in which the cooperating active and passive contact elements function.

Fig. 3 is a detail view showing one ofthe operating parts.

As regards the mode of operation Aof the circuit making contact elements, switching devices may be roughly divided into two classes. One class comprises switching mechanisms in which the active contact elements, such as brushes, are arranged to undergo a comparatively wide range of movement in cooperating -with the stationary or passive contacts. The movable contacts or brushes, for example, in many types of switching structures of this character, are

driven into successive engagement with the stationary contacts with which they coact to establish the proper circuit connection.Y This wide range of movement through which the movable contact elements pass permits them to encounter and traverse in a rubbing manner over the entire surface of the stationary 'contact elements. The rubbing action thus produced serves to maintain both the stationary contacts and the vmovable contacts in a clean and polished condition, insuring good electrical connections at the point of engagement.

Another class of switching structures serving the same purpose of establishing electrical circuit connections comprises those in which the active contact members or elements are adapted to undergo a comparatively slight amount of motion in their cooperation with the passive or stationary contact elements of4 the device. One type of switch belonging to this category is a structure wherein a contact element consists of a conductor of any suitable conformity, such as a. bar, strip, or a bare wire of conducting material. This'contact element is arranged in coopera-tive relation with a plurality of passive contact elements, any oneof which it is adapted to engage. Usually, the movable bar or wire constituting the active contact is of considerable length and is disposed in proximity to each of the several passive contact elements with which it is adapted to make engagement. Due to the particular structure of a switch of this kind, it is only i necessary to move the active element through a comparatively short distance to bring it into physical contact with any one of the passive elements.

Where the movement of the active element required to bring it into physical engagement with a cooperative passive element is slight, the extent of rubbing action is considerably less than in structures of the first mentioned class. To secure this desirable rubbing eil'ect between the cooperative active and passive contacts in order to maintain good electrical contact making surfaces, an arrangement has been devised 1n accordance with the present invention for bodil displacin the movable elements during te period o their physical engagement with the 'passive contact elements.

While the invention is particularly applicable to switching structures of the kind last described, namely, those in which the contact making elements are brought into engagement with one another with la. minimum movement, it is to be understood that the same is not intended to be limited to switches of any particular form or construction.

Referring to the drawing, there is shown one embodiment of the invention in an electrical switching device used for establishing a multiplicity of circuit connections, such, for example, as the circuits of a telephone system. This switching device consists of a frame having the top and bottom support members 1 and 2 and a vertical end support 3 which also acts as a spacing member. The frame members 1 and 2 are provided with a series of slots, not shown, for receiving the slidable drawbars 4, 5, 6, 7, 8, 9, etc. Considering Fig. 1, the length of the structure here illustrated is seen to be sullicient for accommodating six slidable drawbars. Obviously, however, the switch may be of any desired length and as many bars in the row can be provided as the capacity of the structure requires.

The drawbars 4, 6 and 8 are provided at their uppermost ends with retractile springs 51, 52 and 53, respectively, the tension of which normally retains said bars in their extreme upper posit-ion as shown in the drawing. These drawbars at their lower ends after passing through the guiding aperturesin the frame member 2 cooperate with the armatures of the respective actuating electromagnets 10, 11 and 12. The connection between the armatures of the magnets and the drawbars may be of any suitable type. As shown, the armatures pass through apertures in the ends of the drawbars and when the electromagnets are energized, the armatures thereof force the drawbars downwardly against the action of the retaining springs 51, 52 and 53.

Interspersed' between the drawbars 4, 6 and 8 are the three drawbars 5, 7 and 9. The operation of these latter bars is vprecisely the same as the others excepting that they are oppositely disposed in the Structure.

That is to say, drawbars 5, 7 and 9 are normally held by the respective retractile springs 17, 18 and 19 in their extreme downward position. The magnets 13, 14 and 15 for actuating these three drawbars are attached to the top frame member of the structure and their armatures when attracted serve to draw upwardly the bars which they control.

The contact bank of the switch constitutes a plurality of sets of enacting passive and movable bare wire conductons. Although the simplicity of the operation of the switching mechanism shown permits the use of ordinary Wire conductors for the contact making elements, it will be seen that Vthese elements may consist of any suitable form of conductors such as bars, flat stri s, etc. The stationary or passive contact e ements are divided into a plurality of sets, the wires of each set Lvbeing arranged in a, vertical plane and the several sets being spaced horizontally from each other at a convenient distance. As seen in Figs. 1 and 2, the first set of stationary contacts consists of' twelve Wire conductors 26, 27, 28, 29, etc. The second set of stationary contacts is comprised of wire conductors 42, 43, 44, 45, etc., spaced at the proper distance from the first set of contacts. Likewise, as many succeeding sets of stationary contact wires, similarly spaced, may be provided as are required to give the desired capacity. wires are attached securely to side frame members (not shown in the drawing) in any convenient manner. The active or movable Contact elements of the mechanism consist of a plurality of bare wire conductors arranged in intersecting relation with the stationary wires. Fig. 1` illustrates one set oi movable contact wires 22, 23, 24, 25, etc., there being twelve `such wires for cooperation with each of the twelve stationary wires of any set of stationary contacts. The movable wires 22, 23, 24, 25, etc., are secured to thevertical frame piece 3 as shown in Fig. 1. Each of the movable wires has its end twisted to form a helical spring. These springs 54, 55, 56, 57, etc., serve as a. resilient attachment for securing the movable wires at one end to the stationary frame. The movable wires are arranged in n. vertical plane disposed at right angles to the planes containing1 the several sets of stationary wires and pass through apertures 42 in each of the several drawbars 4, 5, 6, 7, 8 and 9. After passing through all of the drawbars the wires 22, 23, 24, 25, etc., are secured to the respective pins 34, 35, 36, 37, etc. projecting from the side of a rotatable cylinder or rod 20. As best seen in Fig. 1, the apertures 42 occurring in the drawbars are so disposed that the movable wires pass through these apertures filst above the corresponding conductors of one stationary set,

These passive contact below the corresponding' conductors of the next stationary set, above the corresponding conductors of the next and so on. That is, each movable conductor is disposed alternatively above and below the corresponding stationary conductor in the successive sets. Normally, the tension applied to the movable conductors 22, 23, 24, 25, etc., by their respective spring members 54, 55, 56, 57, etc., with the drawbars 4, 5, 6, 7, 8 and 9 in their normal positions, is sufficient to hold said movable conductors resting against the edges of the apertures 42 in the several drawbars. The retractile springs such as 51, 52, 53, etc., attached tothe several drawbars are strong enough to hold these bars in their extreme positions when the electromagnets are deenergized to maintain the movable wiresout of contact relation with the stationary wires. By properly balancing the tension of the drawbar springs with respect to the tension of the retaining springs of the movable wires, any required degree of tautness may be a plied to the movable wires without disturblng the drawbars from their normal positions.

As to the capacity of the structure, thls may also be increased in a second direction by providing the proper number of vertical layers of active contact wires and drawbars.

p Fig. 2 shows the capacity extended to three vertical sets or layers of active contacts. These active contacts are arrangedin parallelism with the contacts shown in Fig. 1 and have corresponding points ofcooperation and proximity with the several sets or stationary contact wires. The drawbar 38, for example, corresponds to the drawbar 9 and serves the same purpose of effecting connection between the second set of movable wires and the stationary conductors 26, 27, 28, 29, etc. The same is true of the drawbar 39 correspondingly situated in the third set of movable elements. Electromagnets mounted above and below serve to operate these drawbars as already explalned.

Consider now that feature of the switching mechanism whereby it is possible to secure a rubbing action between the movable and passive contact elements for the purpose of maintaining good electrical contact making surfaces. The cylinder or rod 20 to which movable elements 22, 23, 24, 25, etc., are attached is rotatably mounted between the end pieces of the frames 1 and 2. The tension supplied by the springs 54, 55, etc., of the several movable wires is sufficient to hold the rotatable rod 2() in its normal position as shown in Fig. 1. Attached to the lower end of the rod 20 is an electromagnet element 49 which serves as the armature of an electromagnet 2l. The magnet 21 has a pole piece 46 fashioned in the shape of a horseshoe to present two pole faces 47 and 48. Fig. 3 best shows the disposition of thearmature 49 with respect to the pole .faces 47 and 48 of the pole piece 46. Energization of the electromagnet 21 causes the attraction of the armature 49 against" the pole faces 47 and 48 with the consequent rotation of the rod 20.

The operation of the switch may briefly be described as follows: By any suitable circuit arrangement the particular electromagnet, serving the operating drawbar, which corresponds to the point of cooperation between a desired set of movable and a desired set of passive contacts, maybe selected and energized. Assume, that by such a circuit condition the operating magnety 13 has been energized. The magnet 13 pulls up its armature 16, shown in Fig. 1, and in so doing lifts the drawbar 5 upwardly against the tension. of spring 17 carrying ,the movable conductor 22, 23, 24, etc., into physical contact with the corresponding conductors 30, 31, 32, 33, etc., of the stationary set. By any suitable circuit arrangement a condition is brought about immediately following the energization of magnet 13 for causing the energization of the magnet 21. Magnet 21 rotates the rod 20 whereby the movable conductors 22, 23, 24, etc. are drawn bodily to the right during their engagement with the corresponding conductors -of the sta tionary set. This lengthwise movement of the movable -conductors causes them to slide or rub over the stationary conductors with which they are in Contact. The effect of this rubbing action is to maintain the contacting surfaces in a polished 'condition for insuring good electrical connections. At any convenient time during the engagement of the movable and stationary contact wires the electromagnet 21 may be deenergized ypermitting the springs 54, 55, 56, 57, etc., to withdraw the movable wires in the opposite direction, restoring the rod 20 to its normal position and causing a rubbing action over the stationary wires in the opposite direction. Therefore, for each connection established between a set of stationary and movable contact wires, a rubbing action in both directions may be had by energizing the magnet 21 and causing the same to becomel deenergized during the engagement.

What'is claimed is: l

1. In a switching device, a plurality ot' passive Contact elements, an active contact element having a separate point of cooperation with each of said passive elements, means for moving the active element into engagement with any one of said passive.

passive elements.

3. In a switching device, a plurality of passive contact elements, an active contact element having a point of cooperation with each of said passive elements, a plurality of operating members, one for each point of cooperation, 'for moving the active element o il into engagement with any one of said passive elements, and means for moving the active contact element bodily while in engagement with one of said assive contact elements to produce a rubbing action between said active and passive elements.

v 4. In a switching device, a plurality of passive contact elements, an active contact element having a point of proximity with each of saidpasslve elements, means for moving the active element into engagement with any one of said passive elements, and means for moving the active contact element bodily while in engagement with one of said passive contact elements for producing a rubbing action between said active and passive elements.

5. In a switchingl device, a plurality of passive contact elements, an active contact element arranged in intersecting relation with each of said passive elements, means when moving the active element at the point of intersection with any of said passivev elements for causing engagement between the active element and such passive element, and means for moving the active contact element bodily while in engagement with one of said passive contact elements to produce a rubbing action between said active and passive elements.

6. In a switching device, a plurality of passive contact elements, an active contact element arranged to cooperate at different points throughout its length with said passive elements, means for moving the active element into engagement with any one of said passive elements, and means for moving the active element in the direction of its length While in engagement with one of said passive elements to produce a rubbing action between such active and passive elements. l'

7. In a switching device, a plurality of passive contact elements, a movable wire serving as an active contact element for cooperation with each of said passive elements, means for moving said wire into engagement with any one of said passive elements, and means for moving said wire lengthwise while in engagement with one of the passive contact elements.

8. In a switching device, a plurality of passive bare wires, a movable bare wire serving as an active contact and-arranged in cooperative relation with each of said passive wires, means for moving the movable wire into physical engagement with any one of said passive wires, and means for moving said movable wire in the direction of its length while in engagement with one of the passive wires.

9. In a switching device, a plurality of passive contact elements, an active contact element havin a point of cooperation with each passive e ement, means for moving the active element into engagement with any one of said passive elements, and means for moving sald active contact element first in one direction and then in another direction while in en agement with one of said passive contact e ements.

10.- In a switching device, a plurality of passive contact elements, an active contact element having a point of cooperation with each passive contact, means for moving said active element into engagement with any one of said assive elements, a magnet for moving said) active contact element in one direction, and a sprin for moving said active contact element in t e other direction while in engagement with one of said passive contact elements. j 11. In a switching device, a frame, a plurality of assive bare wires secured thereto, a rotatable element, ,a movable bare ,Wire secured at one end to the frame and at the other end to said rotatable element, means for moving the movable wire into engagement with any one of saidA passive wires, and means for operating the rotatable member to displace said movable Wire longitudinally while in engagement with one of said passive wires.

12. In a switching device, a plurality of passive wires, a plurality of active wires, each having a point of cooperation with each of said passive wires, means for moving any one of said active wiresinto (physical engagement with an one of sai passive wires, and means or moving one of said active wires in the direction of its length while in engagement with one of said passive wires.

- In witness whereof, I hereunto subscribe my name this 7th day of'November, A. D.,

oscAn F. roRsBERG. 

